getting the maximum out of LEDs

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Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=68507
Printed Date: May 15, 2024 at 3:54 AM

Topic: getting the maximum out of LEDs

Posted By: borgreu
Subject: getting the maximum out of LEDs
Date Posted: December 16, 2005 at 5:58 AM

How is it best to connect led's . . .

what connection keeps all leds light at the same brightness??

what connection led's need be connected to bright most??

Thank you for who answers my question

Replies:

Posted By: cowboy21
Date Posted: December 16, 2005 at 6:50 PM

well generaly leds have a range they can run at and the like to run at the average, but can run higher which probably reduces the life of them, now some ppl say u can run up to 4 or 5 leds off one resistor, maybe u can get a little more acurate with power ratings but if u want all of them the same brightness u would be better of running a resistor on each led or 1 resistor for every 2 leds. that is my opinion

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Posted By: nyvr6
Date Posted: December 20, 2005 at 9:35 PM

Click here: How to calculate resistance in ohms

This might help you

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Posted By: total_overkill
Date Posted: January 13, 2006 at 1:40 AM

I run arrays all the time with no problem. 2, 3,4 is as high I as I have gone. I use a 33 ohm resistor at 4. Now when wiring more I run multiple arrays. Say wiring 8 I would wire 2 sets of 4 . Always stick to a prime number in multiple arrays is my law. Don't use 2 sets of 3 and a set of 2 in this case. since you have a set of 2 in there this set will run at a differnt power rating than the other sets of 3.

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Posted By: total_overkill
Date Posted: January 17, 2006 at 4:11 PM

Sorry actually the brightness will depend on what size resistor you use and amount of power supplied to it. After that brightness is dependent on the actual type of LED you use. Not all LEDs are the same and vary vastly.

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40 grit has saved my life sometimes =[

Posted By: firstrax
Date Posted: January 19, 2006 at 10:55 PM

Heres a real simple circuit that uses and adjustable voltage regulator as constant current regulator. When using a constant regulator the voltage can vary without the led brightness changing. This is useful with white LEDs since their brightness can vary greatly with a small change in voltage. Plus you can add LEDs in series without changing the resistor value. You can still get LM317 regulators at radio shack.

The only limitation is that the total foreword voltage of the LEDs in series must be at least 1.5 volts lower than your battery voltage.

A worked example for 3 typical red LEDs: LED foreword voltage = 2.2, current = 30mA

For the resistor, 1.25/0.030 = 41.6 ohm. And at 12 volts you can drive up to 4 LEDs.

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